Despite the availability and consistent use of vaccines against influenza A virus (IAV) in pigs, the disease continues to be an important economic burden for the swine industry. Vaccines used in swine typically consist of whole inactivated virus (WIV) containing an oil-in-water based adjuvant that is administered through the intramuscular route. Other vaccine platforms have been explored, and a non-replicating alphavirus RNA particle that delivers the HA gene as a subunit vaccine is commercially available for swine in the United States. In addition, farms can implement autogenous vaccines. Vaccination is generally performed in breeding females to provide transfer of maternal antibodies to their litters via colostrum, but grower/finisher pigs are occasionally vaccinated as well. While several fully licensed commercial vaccines are available, they are not updated as frequently as the virus evolves antigenically and can result in suboptimal protection against antigenically distinct strains.
Vaccine strategies should be considered on a case-by-case basis and in the appropriate context. Inactivated vaccines can be effective if used in conjunction with other practices, such as controlled movement of animals and people and with careful analysis of whether the vaccine antigen is a good antigenic match with the circulating strain. Knowledge of virus strains circulating up- and downstream of each farm is also necessary. Swine influenza is a dynamic disease that continually evolves, thus monitoring and control strategies need to be intensive and responsive to keep pace. [Read the complete article: Pig333.com, May 9, 2016]